Investigating the role of natural and engineered curli fibers in mediating interactions with the gut epithelium

研究天然和工程卷曲纤维在介导相互作用中的作用 肠上皮 摘要 微生物组在维持肠道功能中的重要性推动了以下研究 共生体和益生菌，试图识别具有治疗潜力的菌株。一个 开发可行疗法的常见策略是使用天然存在的微生物或 识别出能产生所需效果的特定分子制剂并将其制成药物。同时 这种方法取得了一些成功，但由于缺乏对生物学的了解而受到阻碍 机制，无法合理地操纵肠道环境中的有机体适应性，以及 交付机制不完善。我们提出了一种影响主机的替代方法 生理过程的重点是改造细菌产生的基质蛋白 寄主殖民化。具体来说，该提案将确定自然发生和 工程化的卷曲纤维介导肠道内的炎症过程。 Curli 纤维， 是大肠杆菌生物膜的蛋白质成分，已在 致病菌株的背景，因为它们能够介导与宿主组织的粘附，并且 刺激炎症细胞因子的产生。然而，最近的证据表明，纤维 还可以通过增加屏障功能发挥保护作用。有趣的是，益生菌大肠杆菌 菌株（尼塞尔），通常用于帮助维持炎症性肠病的缓解 众所周知，IBD 患者在体外会产生大量的卷曲纤维。我们将利用基因 改造尼塞尔菌株以确定卷曲纤维在调解中的作用程度 肠道的炎症过程。同时，我们将创建尼塞尔菌株 被设计为在其卷曲纤维上显示抗炎细胞因子。这些功效 将使用体外和体内相结合的方法来测量各种经过基因改造的尼塞尔菌株 体内模型系统。值得注意的是，我们将利用我们开发的 Gut-on-a-Chip 系统 合作者深入了解 Curli 纤维-上皮相互作用的分子机制。 该系统能够研究高级上皮功能，如屏障功能、绒毛功能 高度和粘附力，比传统的 Transwell 检测好得多。我们提议的合作 该系统还将有助于验证其作为益生菌快速筛选技术的作用。组合起来 通过建立慢性肠道炎症小鼠模型，这些模型系统将促进 有效鉴定和开发具有慢性病治疗潜力的微生物 肠道炎症。这也是我们实验室建立生物膜基质的更广泛努力的一部分 蛋白质可以成为治疗递送和益生菌靶向的多功能新平台。

Investigating the role of natural and engineered curli fibers in mediating interactions with the gut epithelium Abstract The importance of the microbiome in maintaining gut function has fueled the study of commensals and probiotics in an attempt to identify strains with therapeutic potential. A common strategy to develop viable therapeutics is then to use the naturally occurring microbe or identify a specific molecular agent that leads to the desired effect and make it into a drug. While this approach has seen some success, it is hindered by a lack of understanding of biological mechanisms, an inability to rationally manipulate organismal fitness in the gut environment, and inadequate delivery mechanisms. We propose an alternative approach to influencing host physiological processes focused on engineering the matrix proteins produced by bacteria during host colonization. Specifically, this proposal will determine the role of naturally occurring and engineered curli fibers in mediating inflammatory processes inside the gut. Curli fibers, which are a proteinaceous component of the E. coli biofilm, have been studied extensively in the context of pathogenic strains because of their ability to mediate adhesion to host tissues and stimulate inflammatory cytokine production. However, recent evidence suggests that the fibers may also play a protective role by increasing barrier function. Interestingly, a probiotic E. coli strain (Nissle) that is commonly used to help maintain remission in inflammatory bowel disease (IBD) patients, is also known to produce copious curli fibers in vitro. We will use genetically engineered strains of Nissle to determine to what extent curli fibers play a role in mediating inflammatory processes in the gut. Simultaneously, we will create Nissle strains that are engineered to display anti-inflammatory cytokines on their curli fibers. The efficacy of these various genetically altered Nissle strains will be measured using a combination of in vitro and in vivo model systems. Notably, we will make use of a Gut-on-a-Chip system developed by our collaborators to gain insight into the molecular mechanisms of curli fiber-epithelium interactions. This system enables the study of higher-order epithelial functions, like barrier function, villus height, and adhesion, much better than conventional transwell assays. Our proposed work with this system will also help validate it as a rapid screening technique for probiotics. In combination with established mouse models of chronic gut inflammation, these model systems will facilitate efficient identification and development of microbes with therapeutic potential against chronic gut inflammation. This is also part of a broader effort in our lab to establish that biofilm matrix proteins can be a versatile new platform for therapeutic delivery and probiotic targeting.